![]() The decryption algorithm proposed by Passcape merely simulated DPAPI operation, so the DPAPI system has not been compromised. In 2005, the company released the first commercial application (Outlook Password Recovery) based on that recovery, which could decrypt DPAPI blobs offline, i.e. Perhaps, that's the reason why the internal structures and operating principles of DPAPI had been kept behind a closed curtain for so long.įor the first time, DPAPI was analyzed by Passcape Software in 2003. ![]() DPAPI has become popular among programmers first of all due to its simplicity of use, as it consists of just a couple of functions for encrypting and decrypting data, CryptProtectData and CryptUnprotectData.ĭespite its apparent simplicity, the technical implementation of DPAPI is rather complicated, and these functions' operation logic is much like the cheerful childish rhyme "The House that Jack Built". For example, in the file encryption system, for storing wireless connection passwords, in Windows Credential Manager, Internet Explorer, Outlook, Skype, Windows CardSpace, Windows Vault, Google Chrome, etc. ![]() DPAPI is currently widespread and used in many Windows applications and subsystems. We hope these tools, as well as certain information from our article, is found interesting not only to experts and criminologists but to all researchers in the field of computer security.īeginning with Windows 2000, Microsoft ships their operating systems with a special data protection interface, known as Data Protection Application Programming Interface (DPAPI). The operation of DPAPI was analyzed using a set of 6 utilities, integrated into one of the most powerful applications for auditing Windows passwords, Windows Password Recovery. For the first time ever, we practically tested the user logon password recovery algorithm without using SAM or NTDS.DIT files. Much attention is paid to the recovery of DPAPI data when user profile cannot be loaded. Additionally, a deeper analysis of the implementation of the first version of DPAPI, released along with Windows 2000, has revealed the presence of a number of serious vulnerabilities and put the entire security of the system into question. We also attempt to point out some functional drawbacks of the latest version of DPAPI and possible ways to eliminating those. The paper presents the world's first complete (not claiming to be universal though) description of DPAPI operation logic and all the undocumented structures, including DPAPI blobs, Master Keys and credential history files. In this paper, we are making an attempt to analyze the operation of DPAPI, review the undocumented structures and encryption algorithms of DPAPI, understand and describe the internal functioning of the system. ![]() Decrypting credential history hashes from DPAPI.Recovering user password without loading hashes from SAM/NTDS.DIT.Recovering wireless connection passwords in Windows 7.Looking for DPAPI blobs in registry and Active Directory.Forced password reset (stanalone PCs under Windows XP - Windows 7).What happens when changing Windows password Backing up Master Keys and restoring them from backups.Examples of use for CryptProtectData/ CryptUnprotectData functions.Description of CryptProtectData and CryptUnprotectData functions.
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